The Food and Drug Administration is expected to decide whether it will regulate them this month. In the meantime, more than half the states have already restricted their sales.

Are electronic cigarettes safe or do they carry health risks of their own? Should states regulate them? The answers depend on whom you ask. But before the end of this month, the Food and Drug Administration is expected to decide whether it will regulate them along with traditional cigarettes.

It’s safe to say that the jury is still out on many of these questions. States, the federal government and lobbyists on both sides of the issue are talking about whether e-cigarettes should be regulated, how and by whom.

Electronic cigarettes use rechargeable batteries, electronic controls and cartridges of a liquid chemical mixture of nicotine, propylene glycol and other chemicals. The system vaporizes the liquid, which can be “vaped”—the hip neo-verb for inhaled. Most look like tobacco products, but some even resemble pens and USB flash drives for stealth puffing.

According to the World Health Organization, the cartridges typically contain between 6 and 24 mg of nicotine but sometimes have more than 100 mg. Nicotine, though highly addictive, isn’t what causes health problems like cancer and heart disease—it’s the 600 other ingredients in tobacco products, which can create at least 50 of which are cancer-causing chemicals.

That’s why e-cig fans (manufacturers, most powerfully) are positioning them as nicotine-replacement products, like nicotine gums and patches, to help smokers wean off tobacco. Opponents counter that enough isn’t known whether e-cigs work to that end, or if the vapor itself may be harmful.

The science, so far, is contradictory.

Modern Healthcare magazine reports that one study of e-cigarette models claimed they produced formaldehyde at close to the levels in tobacco cigarettes, and a 2009 FDA study found toxic chemicals in e-cigarette vapors such as diethylene glycol, an ingredient used in antifreeze. Another study published in the journal Chest in 2012 found changes in the lung functions of healthy smokers who puffed on an e-cigarette for as long as five minutes. But an analysis by the Drexel University School of Public Health found “no serious concern about the contaminants such as volatile organic compounds in the liquid or vapor produced by heating.”

What to do? The FDA’s attempt to ban the products in 2009 was blocked by an appeals court in 2011. Since then, the feds have effectively sat this one out. Last month, 40 state attorneys general signed a letter urging the FDA to rejoin the fight and assume “immediate regulatory oversight of e-cigarettes, an increasingly widespread, addictive product.” That letter also referenced a Centers for Disease Control and Prevention-issued “emergency note from the field” that reported about 21 percent of adults who smoke traditional cigarettes had used e-cigarettes, up from about 10 percent in 2010. It estimated that 1.78 million middle- and high-school students had tried e-cigarettes during 2012.

“If large numbers of adult smokers become users of both traditional cigarettes and e-cigarettes—rather than using e-cigarettes to quit cigarettes completely—the net public health effect could be quite negative,” said Tim McAfee, M.D., director of the Office on Smoking and Health at CDC.

While the feds dither, states are acting.

More than half the states—including Maryland, Kentucky, Minnesota, New Jersey, New Hampshire, Tennessee, Utah, Wisconsin, California and Colorado— and some cities such as Hermantown, Minn., and Hastings, Mich.—restrict sales in some way. Countless others are considering it, and state legislators across the country have introduced more than 35 proposals calling for some type of regulation of electronic cigarettes in various states, says Karmen Hanson, health program manager for the National Conference of State Legislatures.

“States have shown an interest in regulating these products, and until the feds take an official stance, the states are taking the lead in doing what’s best for them,” she says.

Many public health leaders are cheering them on. The WHO states, flatly, “The safety of ENDS has not been scientifically demonstrated. The potential risks they pose for the health of users remain undetermined. Furthermore, scientific testing indicates that the products vary widely in the amount of nicotine and other chemicals they deliver and there is no way for consumers to find out what is actually delivered by the product they have purchased. … Until such time as a given ENDS is deemed safe and effective and of acceptable quality by a competent national regulatory body, consumers should be strongly advised not to use any of these products, including electronic cigarettes.”

Laurie Fenton Ambrose, president and CEO of the Lung Cancer Alliance, says her organization “supports FDA regulation of these electronic cigarettes. Clearly the jury is still out as to whether such cigarettes promote cessation. Tobacco manufacturers are continuing to target young people with candy-like flavors, flashy colors and cool names while claiming to target folks who are trying to quit. Regulation by the FDA is both urgent and prudent to protecting our children and public health.”

Georges Benjamin, M.D., executive director of the American Public Health Association, pulls no punches either.

“I have seen the ads for these products, and they take us back to the Joe Camel days,” he says. “My experience with the tobacco industry tells me the likelihood is it will do more harm than good. I know the tobacco industry, and I don’t trust them one bit.”